Aquatic Invasive Species

What are Aquatic Invasive Species?
Aquatic Invasive Species (AIS) are invasive plants that live on, in or near water or invasive animals that require a watery habitat (USDA). Invasive species share the following characteristics:
1. They are not native to the ecosystem. Some species may be native to the United States, but not Wisconsin; some could even be native to one part of the state, but not another!
2. Invasive species cause economic and/or ecological harm (e.g. crowding out native species, clogging water intakes, reducing commercial catches, etc.)
3. They often spread quickly because of prolific reproduction and/or a lack of native predators; in their native habitats, invasive species probably have predators keeping their numbers in check, but in their invaded habitat, there's often nothing to eat them and stop their spread.

What Can You Do?

Learn about the invasive species in the areas where you boat/fish. Visit the municipal boat launches to see brochures (or download here) and kiosks with more information.
Always follow the Wisconsin DNR's steps for preventing the spread of AIS:

Inspect boats, trailers, and equipmentRemove all attached aquatic plants and animalsDrain all water from boats, vehicles, and equipmentNever move plants or live fish away from a water body

Watch out for...Hydrilla and Brazilian WaterweedIdentification: Hydrilla has small, spiny leaves with pointed tips in whorls of 3-10 around the stem. It has spiny midribs on the underside of its leaves. It grow underwater and branches out close to the surface. Brazilian Waterweed has finely serrated leaves in whorls of 3-6. It can be distinguished from Hydrilla by the smooth midribs under its leaves.

Impact: Both plants form thick mats that shade or crowd out native species and hinder boating and swimming.

Eurasian Water Milfoil
Identification: It grows underwater, except for a flowering spike above the surface. Its leaves are in groups of four whorled around the stem and made up of smaller leaflets. Impact: It forms dense mats that shade out native species, hinder recreation, and clog pipes.
(Barry Rice, Sarracenia.com, Bugwood.org)

Common Reed
Identification: It can grow over 15 feet tall with green or tan stems and flat, greyish green leaves. Plumes at the top of the plant are dense and feathery. Impact: It spreads rapidy and grows densely in wetlands and along shores, crowding out native species.
(Jil Swearingen, USDI NPS, Bugwood.org)

Purple LoosestrifeIdentification: Stalks are woody and can grow over 6 feet tall, while leaves are downy with smooth edges. Flower spikes have small purple flowers with yellow centers. Impact: They produce millions of easily spread seeds each year, crowding out native plants and reducing wildlife food sources and habitat.
(Norman Rees, USDA Agricultural Research Service, Bugwood.org)

Japanese KnotweedIdentification: Stems are reddish brown and resemble bamboo. Leaves are spade-shaped. Flowers are whitish green and are in clusters resembling plumes.

Impact: Japanese knotweed, while not an aquatic invasive species, invades riparian areas. It colonizes easily, leading to dense thickets that prevent native species from growing. Japanese knotweed also produces chemicals that are toxic to other plants.

(US Fish and Wildlife Service)

Zebra and Quagga MusselsIdentification: Both species have tan bodies with bands of color. Quagga mussels have a more rounded shape than zebra mussels, which are triangular. Zebra mussels have one flattened side, as well as thread-like attachements that help them attach to the substrate. Both can be as small as half an inch. Impact: Both species compete with fish for food, clog pipes, and alter ecosystems by increasing clarity of water.
(Amy Benson, USGS, Bugwood.org)

New Zealand MudsnailsIdentification: They are typically around 5 mm in size. Their shells are light to dark brown with 5-8 whorls. Impact: New Zealand mudsnails are able to outcompete native species by surviving in many conditions, reproducing quickly, and competing for food and habitat.
(Mohammed El Damir, Pest Management, Bugwood.org)

Spiny and Fishhook WaterfleasIdentification: Spiny waterfleas' bodies are 1.5 cm in size. They have a pointed tail with spines. Fishhook waterfleas are 6-13 mm in size. They are transparent and have an angled tail with three barbs and a hook at the end. Impact: Both species compete with native fish for food. Spiny waterfleas can damage fishing equipment.
(Jeff Gunderson, Minnesota Sea Grant Program)

Freshwater JellyfishIdentification: They grow to be .5-2.5 cm. They are transparent and gelatinous with tentacles. Impact: Freshwater jellyfish compete with native species for food.

Rusty CrayfishIdentification: Rusty crayfish are larger than other crayfish species. They have a rust-colored spot on each side of their bodies and black bands on the tips of their claws. Impact: They displace native species through aggression and competition for food. They also destroy aquatic plants.
(USGS Archive, USGS, Bugwood.org)

Red Swamp CrayfishIdentification: Adults have dark red bodies with long, narrow pincers and wedge-shaped black stripes on their abdomens. Juveniles have grey bodies. Impact: They compete with native crayfish species for food and habitat, spread diseases, and impact amphibian populations through predation and habitat competition.(Chris Taylor, IL History Survey, Bugwood.org)

Round Goby
Identification: Females and juvenile males are mottled grey and brown, while spawning males can be almost completely black. They have large, round heads and fused pelvic fin on their underside. They look similar to native sculpin. Impact: Round gobies are very aggressive. They compete with native species for food and habitat.(Center for Great Lakes and Aquatic Sciences Archive, University of Michigan, Bugwood.org)

Sea Lamprey
Identification: They are eel-like and 12-20 inches long. Their backs are dark brown or black and their undersides are grey or pale brown. They have one long dorsal fin and a circular mouth with rows of teeth. Impact: Sea lampreys attach to other fish and suck on blood and bodily fluids. A lamprey can eat more than 40 pounds of fish in its lifetime.(Lee Emery, USFWS, Bugwood.org)

Sponsors
Development of the municipal boat launch kiosks, AIS brochures, and this webpage were funded by the Wisconsin Coastal Management Program and the National Oceanic and Atmospheric Administration, Office of Ocean and Coastal Resource Management under the Coastal Zone Management Act, Grant #NA12NOs4190091.

Assistance with development of the informational materials was provided by Carrie Sanda, Douglas County AIS Coordinator.